1. Field of the Invention
The present invention relates generally to the field of wireless communication, and, more specifically, to uplink power control. Although the present invention is subject to a wide range of applications, it is especially suited for use in a cellular communication system, and will be described in that connection.
2. Description of the Related Art
Technical Specification 3GPP TS 25.211 v5.0.0 (2002-03), 3rd Generation Partnership Project (3GPP); Technical Specification Group Radio Access Network; Physical channels and mapping of transportation channels onto physical channels (FDD) (Release 5) provides for a High Speed Downlink Shared Channel (HS-DSCH). The HS-DSCH is a downlink transport channel shared by one or several user equipment (UE).
In 3GPP High Speed Data Packet Access (HSDPA), a UE can be in soft handoff (SHO) with multiple Node-Bs for the Dedicated Physical Channel (DPCH) on downlink. There is, however, no HSDPA SHO for the High Speed Downlink Shared Channel (HS-DSCH) and corresponding uplink High Speed Dedicated Physical Control Channel (HS-DPCCH). This may result in a condition called link imbalance. That is, the Node-B serving the high speed data over the HS-DSCH is different from the Node-B to which the UE has the best uplink for the DPCCH.
A need therefore exists for apparatus and methods for uplink power control during link imbalance that considers the reverse link HS-DPCH.